From Rice to Shrimp

It’s the rainy season here in Tran De. About a dozen field workers have squished out into a green paddy that goes on for more than two and a half football fields.

They chatter in Khmer as they bend low and pull young rice plants from their monsoon-soaked beds, and toss them into piles for replanting.

“I was born in this area, I’m from this area,” says a 64-year-old farmer named Minh. “I learned from my father and my grandfather, from the time I was a kid, how to grow rice.”

Minh is renting the land to grow his crop. “Rice is good,” he says, “you can always eat it. It’s reliable.”

At least right now it is.

Some of Hai Thach’s usually green fields are starting to yellow. He says that’s a sign of saline intrusion. (Photo: Christopher Johnson)

Things will change when the dry season starts in January. That’s when farmers here usually start raising a rice crop, typically relying on fresh water they pump or channel in from some branch of the Mekong River.

But the dry season has been getting dryer. And the South China Sea – less than a mile away – is rising and pushing up into empty river and stream beds.

What little fresh water there is goes salty. So does the soil.

Once that happens, rice farmers like Minh know their crops are history.

“This village is affected by saline intrusion,” he explains. “During the dry season, people here can’t do anything with the land. They just leave it, go somewhere else and work, or try to find some work locally.”

If Minh risked planting a dry season crop, he could earn more than $2,000.

But he won’t take that chance. Instead of fighting saline intrusion, he’s found a way to hedge his bets and make some money off climate change.

Many rice farmers are switching to saltwater shrimp as a crop, to eliminate risk from salinization. Paddles aerate a shrimp pond, adding oxygen to the water. (Photo: Christopher Johnson)

He’s gone and bought himself a shrimp farm.

So has another farmer, named Sung. Standing beside two shrimp ponds out behind his house, Sung fires up what looks like a system of small spinning steamboat paddles.

They’re adding oxygen to an opaque brown pool.

This salty water is killing off the region’s rice, while the shrimp, somewhere down at the bottom, are loving it.

They can earn Sung in a year more than four times what an average rice farmer brings home.

“In a good year,” Sung says, “I do two crops. If it hits, I get $4,720 from these two ponds. This is the only thing I can do. Growing rice is not very profitable.”

With very few choices, explains Tim Gorman, a Cornell grad student researching how peoples’ lives in the Mekong Delta are being changed by global warming, some farmers are turning away from rice.

“The biggest option to people here in these areas affected by saline intrusion,” Gorman explains, “is to abandon rice altogether and switch to saltwater shrimp.”

This has been a “winning strategy” for many people in the area, Gorman observes. “Just driving around here you can see that there are big new houses, you see some nice new cars. And so you have some people who really have made a lot of money from growing shrimp, which is primarily exported to markets in Europe, Asia, and the US.”

A shrimp farmer named Sung pulls a basket loaded with shrimp from the bottom of one of his ponds. (Photo: Christopher Johnson)

Shrimp farmer Sung isn’t doing quite that well. He’s helping his daughter pay for college, but there’s no fat new Mercedes in the driveway.

That kind of money goes mostly to big-time farmers. Some people earn tens of thousands of dollars a year in the shrimp trade. With the lure of five and six-figure profits, plus faltering rice crops killed off by rising seas, Gorman says some folks are even taking hammers to the very gates and dykes set up to protect the area from the ocean.

“People are actively manipulating the infrastructure,” he says, “sabotaging the infrastructure, to allow salt water to come in. Not just during the dry season, but all year, so they can switch from freshwater rice farming to saltwater shrimp farming.”

Shrimp is no sure bet, either. Seeds, antibiotics, aeration systems, start-up costs – kilo for kilo, it’s way more expensive to raise than rice. A few sick ones can take out a whole pond.

Sung says he’s gone bust before. “In a bad year, all I have left are the whites of my hands!”

That’s the risk for most farmers here – rice, shrimp, or anything else.

But more and more, those who can afford it are moving away from rice and putting their money down on a changing climate.

Christopher Johnson is a freelance journalist who has worked in public radio as a producer, reporter, editor, commentator, and manager.

Future Sea Level

A break with the past

In the late 1990s, a dramatic event surprised and disturbed glaciologists around the world, increasing concern that global warming could cause Earth’s great ice sheets at the north and south poles to disintegrate rapidly and catastrophically. A frozen stream of ice in the Jakobshavn Glacier on Greenland’s west coast suddenly accelerated seaward. Already one of the world’s fastest moving glaciers, Jakobshavn doubled its speed.

Jakobshavn glacier in 2013Photo: Gretel Ehrlich

Mountainous blocks of ice broke off Greenland’s perimeter at a furious rate, clogging a 35-mile long fjord with icebergs bigger than aircraft carriers. Fortunately, Jakobshavn settled down several years later. But before it did, the glacier had expelled tens of billions of tons of ice into the Atlantic.

Scientists aren’t sure why Jakobshavn sped up, or tapered off later. They haven’t been able to calculate the top speed that an ice stream like Jakobshavn could achieve. Nor can they specify the limit of how much mass such streams of ice in Greenland or Antarctica could cast into the sea. They’d dearly like to know, as many researchers believe the accelerated flow of solid ice in ice streams could dramatically increase the rate of sea level rise. Until these questions are resolved, some researchers consider it possible that sea level rise later this century could be many feet.

Global warming basics

Earth is getting hotter. The planet has heated up by around 1.5 degrees Fahrenheit (0.8 degree Celsius) since the 1880s. When the oceans heat up, their water expands and creeps up shorelines. Higher temperatures also threaten mountain glaciers and the huge ice sheets at Earth’s north and south poles. Since extra heat also cranks up evaporation and precipitation, sometimes in the form of snow that compensates for melting, higher temperatures don’t necessarily always make glaciers shrink.

In practice, though, scientists have discovered that all the world’s major glaciated mountain ranges including the Andes, the Himalayas, the Swiss Alps and the mountains of Alaska are losing ice. The continental-size ice sheets of the poles are shedding massive amounts of mass into the sea. As a result, sea level has gone up by about 4.5 inches (11 centimeters) since 1950. The rate at which sea level is increasing appears to be going up, though researchers can’t be sure until more time has passed.

About 40 percent of the world’s inhabitants work and farm and sleep within about 50 miles of a coastline. The sea laps the land of eight of the world’s top ten cities. As the sea rises, many of these people are threatened with increased flooding, storm damage and salt intrusion into groundwater. Billions of dollars of property and millions of lives are at risk.

How fast and how high might sea level grow in the future? Government planners and residents of coastal regions are among the many people who could plan better if they knew the answer. Scientists have made estimates of future sea level. But their results are uncertain because the task is complicated by the numerous factors that influence sea level rise.

Earth’s ice

Ice occurs naturally in various forms in many parts of the world. Each kind has its own particular relationship to global warming and sea level. When viewed from space, Earth’s most obvious feature, after the oceans, is, a vast white wintertime band of snow covering northern Asia, Europe and North America. Global warming will reduce the amount of land covered in snow. But that melted snow will have virtually no impact on sea level. That’s because the layer of snow is thin, and the volume of water in snow is dwarfed by the vastness of oceans.

Icebergs near GreenlandPhoto: Gretel Ehrlich

The second most noticeable form of frozen water on Earth is sea ice. Sea ice, as the name suggests, is water frozen on the ocean’s surface, generally near the poles. The amount of sea ice varies with the seasons. At its maximum extent, such ice covers about 10 million square miles of water, an area about the size of ten Australias. The amount of sea ice in the Arctic has been declining steadily for at least as long as systematic satellite monitoring began in the late 1970s. Many researchers predict that the Arctic will be virtually free of sea ice in summers before the middle of this century; perhaps much sooner.

The disappearance of sea ice will not alter sea level. That’s because sea ice floats, just like ice cubes in a drink. When a soda on the rocks warms up, the level of the surface remains fixed. (However, the loss of sea ice will have numerous other detrimental effects. Sea ice reflects sunlight back into space, whereas ocean water absorbs most sunlight that hits it. Less sea ice means a warmer Arctic. The temperature differential between the Arctic and equatorial regions, a major force behind Earth’s weather patterns, will be muted.

Moreover, sea ice performs important roles in polar ecosystems. Marine mammals such as some seals and polar bears depend on it as a platform for hunting and resting. Many of the marine plants that form the foundation for the polar food chain, known as phytoplankton, also depend on sea ice for part of their life cycle.)

Unlike sea ice, the huge ice sheets of Antarctica and Greenland rest on land (or, in some cases, the seafloor). Sea level does rise when they melt. The ice sheets occupy less area than sea ice or snow, but they’re radically thicker (more than a mile, or about 1.6 kilometers, from top to bottom in places). All together, the polar ice sheets hold enough water to lift sea level by about 250 feet (76 meters). Mountain glaciers also raise sea level as they recede, which they’re doing, at a spectacular rate. But mountain glaciers hold only a small fraction of the water stored in polar ice sheets: only enough to raise sea level by about 2 feet (0.6 meters).

Unlike ice cubes

Because polar ice sheets are so massive, the rate at which they might melt has received concerted scientific attention. Still, many questions remain. If ice sheets behaved like an ice cube dropped out of a freezer tray on a summer day, predicting how fast they’d waste away—and how fast sea level would rise—would be relatively easy.

Ice cubes melt from the outside inward. As the exterior dribbles off, inner ice appears in an orderly fashion, like layers peeled off an onion. To predict the fate of ice melting this way requires taking into account factors like air temperature and the movement of air currents. Scientists know how to perform such calculations for ice cubes as well as for ice sheets. Researchers have estimated, roughly, that if all the world’s glaciers melted this way, sea level rise by about 15 inches (0.4 meters) by the end of the century. Sea level rise of this magnitude can’t be ignored, but it’s relatively small, and it would occur over many decades.

But, while behaving in part like ice cubes, ice sheets also waste away in a manner unlike any ice cube: from the inside out. Frozen ice streams convey an ice sheet’s bulk from the interior to the perimeter at the sea, sometimes hundreds of miles away. At the edge of the ice sheet, great blocks shear off and fall into the water. An ice sheet flowing this way could lose volume much faster than one that suffers surface melting alone.

Alternate Approaches

There are two primary means of forecasting future sea level. In one, scientists create a mathematical model of sea level that takes into account how much water will expand and how much glaciers will grow or shrink. This method requires a detailed understanding of factors like how heat penetrates into the ocean’s depths, how changes in air temperature influences precipitation and, of course, the behavior of warming glaciers. Researchers have created such models. But they suffer from uncertainty about how Earth’s complex parts work and relate to each other.

Blowing Rocks Preserve, Florida

The other major way that scientists try to predict future ocean inundation is by studying sea level in Earth’s past, when the planet was as warm or warmer than today. For the last two million years or so, Earth has cycled more than a dozen times between ice ages and warm periods. The last ice age ended about 12,000 years ago. Scientists think these temperature swings are controlled in part by changes in Earth’s orbit around the sun. During an ice age, billions of tons of water freezes on mountaintops and at the poles. Sea level falls hundreds of feet. During a warm period, in contrast, this ice melts, ocean basins swell with the extra liquid, and the seas rise.

Climate researchers are especially interested in how high the sea rose during previous warm periods, prior to the most recent ice ages. Several such epochs have been hotter than today, making them possible analogs to our warmer future. The most recent warm period, about 100,000 years ago, was 2 to 4 degrees Fahrenheit (1 to 2 degrees Celsius) warmer than today. Many scientists believe that sea level was 15 to 20 feet higher then.

Choosing whether to act

Earth’s temperature will rise sharply unless steps are taken to reduce significantly the amount of fossil fuel burned to make electricity, power vehicles and to heat homes. We’ll have to make heroic efforts to prevent global temperature from reaching or surpassing that of the last warm period.

If Earth does get that hot, many scientists believe that sea level will rise to the level it reached during that earlier spell. They readily admit, however, that they can’t predict how quickly the sea would go up.

They’ve uncovered evidence that within the past 20,000 years sea level has gone up at a rate as fast as 12 feet (4 meters) per century. However they can’t say if global warming could cause sea level to rise that quickly in the future.

More on last week’s invite-only rising seas meeting

Alex Chadwick, BURN Host

After my last post on the Union of Concerned Scientists and the meeting in New York last week about sea level rise, I got a note back from UCS. I was very critical of their closing this meeting to the public and press. The meeting was attended by local officials from New York, New Jersey, Virginia, North Carolina and Florida. Emergency responders, natural resource managers – the people who are going to try to manage the climate changes that are beginning now, and which are certain to grow.

A press person at UCS wrote to say she was disappointed in the blog. Among the things she pointed out: I never said in my blog that UCS had a press conference in the middle of the day, and that they put up a panel of a half-dozen participants and took questions.

UCS is correct. I should have noted that. In fact, I was in New York, and went to the press conference, and found it very useful. I’m taking information and contacts from it for a story that I hope might break through a general numbness to climate reporting – I don’t think it gets the public attention it deserves.

It’s a transformative story in many ways, and the climatic changes are going to make for very difficult times. Those changes are directly tied to our energy use, but not something we take into account in the energy choices we make. Or not seriously. More open discussion of what is coming is better, I think.

So, I have disappointed the Union of Concerned Scientists, and they have disappointed me. We exchanged another series of notes today and agreed to go on talking.

Why you can’t attend a rising seas conference in NY

Alex Chadwick, BURN Host

This week, in New York City, the Union of Concerned Scientists is convening a meeting of dozens of public officials from New York, New Jersey, Virginia, North Carolina and Florida to talk about one of the most serious issues these officials are facing: rising sea levels brought about by global warming, the product of greenhouse gases. Some of these officials dealt with Hurricane Sandy – the one that left parts of Manhattan without power for five days and battered the New Jersey coast. Others, especially in Florida, already see evidence of climate change – not from storms, but simply in the tides. The officials are meeting with one another for conversations, with a few scientists on hand to offer guidance.

They will be there – but the public will not. UCS, which describes itself as a coalition of citizens and scientists working to better public policy and corporate practices, has closed the meeting.

I learned of the event a month ago through one of the participants. I sent UCS a note asking to go, and dropped what I thought would be our best card with this group – we were just recognized by the American Association for the Advancement of Science for best radio science reporting. I though of this as an opportunity to meet and listen to the people who are going to be creating the policies and practices that will be of ever greater significance in this country, as more and more lives and enormous swathes of property are at increasing risk.

The response from UCS was that it would be ‘unwieldy’ to allow reporters to observe. And no one from the public, either.

A citizen who might think s/he would like to know more about rising sea levels? No, not this time, they said. Unwieldy.

I’ve known the Union of Concerned Scientists to be public-minded advocates of science-based solutions to all sorts of issues. They’re tough-minded and fearless in their frequent papers and testimony. But when I protested the exclusion of reporters and others from this meeting, a UCS press person said that climate has become so controversial that they worried about hecklers, or trouble-makers – people who would show up for theatrical opposition.

If UCS is going to close a meeting because some nut-job – or even a true skeptic, though many believers doubt there is such a thing – might show up and try to disrupt things, then we are in worse shape than I thought. These are public officials, at a meeting convened by a science organization that boasts of its citizen involvement. And they want to talk just among themselves because an outsider might be argumentative – even disruptive?

A spokeswoman told me a week ago that they’d think about opening the meeting. She’d tested the idea on one official already, and the response was that UCS would be changing ‘the rules’, and thus the official might not attend. Wonderful. If UCS and public officials are doing such a great job getting out the climate message, where is the public consensus about the urgency of doing something?

UCS and public officials have done such a great job getting out the climate message that there is noted consensus about the urgency of doing something. So, okay, maybe we should just leave them alone in a room, talking to each other. But when they close the doors, I hope there’s a flicker of shame somewhere inside there.